AAAA is a domain record, that's essentially the IPv6 address of the server in which the domain is hosted. The IPv6 system was intended to replace the existing IPv4 system where each and every IP is made up of four sets of decimal digits between 1 to 255 e.g. 126.96.36.199. In comparison, an IPv6 address has 8 sets of 4 hexadecimal digits - ranging from 0 to 9 and from A to F. The reason for this change is the significantly smaller range of unique IPs the current system supports and also the fast increase of units which are connected to the Internet. An illustration of an IPv6 address is 2101:1f34:32e2:2415:1365:4f2b:2553:1345. If you want to point a domain address to a machine that uses this type of an address, you'll have to set up an AAAA record for it, not the widespread A record, that is an IPv4 address. The 2 records provide the exact same function, yet different notations are used, in order to differentiate the two types of addresses.